[dpdk-stable] [PATCH 18.11] kni: fix ethtool build error on kernel 5.9

[Luca Boccassi]

On Mon, 2020-11-23 at 14:49 +0000, Kevin Traynor wrote:
> read_barrier_depends() is removed from kernel 5.9 as per Linux
> commit 93fab07c2293 ("locking/barriers: Remove definitions for [smp_]read_barrier_depends()")
> 
> It is used by ethtool and produces an error when building on kernel 5.9:
> 
> /kernel/linux/kni/ethtool/igb/igb_main.c: In function ‘igb_clean_tx_irq’:
> /dpdk-stable/kernel/linux/kni/ethtool/igb/igb_main.c:7067:3:
> error: implicit declaration of function ‘read_barrier_depends’
> [-Werror=implicit-function-declaration]
>  7067 |   read_barrier_depends();
>       |   ^~~~~~~~~~~~~~~~~~~~
> 
> Fix by replacing with rmb() as is done for < 2.6 kernels.
> 
> Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
> ---
>  kernel/linux/kni/ethtool/igb/kcompat.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/linux/kni/ethtool/igb/kcompat.h b/kernel/linux/kni/ethtool/igb/kcompat.h
> index 459fda3dad..e89033818a 100644
> --- a/kernel/linux/kni/ethtool/igb/kcompat.h
> +++ b/kernel/linux/kni/ethtool/igb/kcompat.h
> @@ -3974,3 +3974,7 @@ skb_set_hash(struct sk_buff *skb, __u32 hash, __always_unused int type)
>  #endif
>  
> +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 9, 0)
> +#define read_barrier_depends() rmb()
> +#endif
> +
>  #endif /* _KCOMPAT_H_ */

Acked-by: Luca Boccassi <bluca at debian.org>

-- 
Kind regards,
Luca Boccassi